Potato (.L) which originated in South America was first introduced into Nigeria in the later part of the 19 century and early 20 century by Europeans, notably the tin miners in Jos Plateau and the Germans in the Cameroons (Stanton, 1960, Ifenkwe, 1981. Early potato production in Nigeria was centered around Zaria and Plateau provinces,. Annual production was however low until the beginning of the second World War in 1944, (William, 1962. Plateau Province accounted for about 67% of the total potato production in 1944. After World war two, production did not substantially increase until 1973 (Okonkwo 1995a). After 1960, there was an attempt by the post colonial government of Nigeria to increase potato production. Seed tubers were imported from the United Kingdom by the then Ministry of Agriculture, Northern Region in collaboration with the Pankshin Native Authority for distribution to selected farmers. As demand for seed increased, a seed multiplication scheme was established by the Ministry of Agriculture, Jos and Pankshin Native Authority. This seed multiplication scheme contributed to increased potato production recorded in the early seventies. However, the varieties imported were low yielding and susceptible to major diseases and pests of potato in the area. Potato is a tuber crop, grown in high altitude areas with low temperatures. The high altitude areas for potato production in Nigeria are the Jos plateau (1400m) in Plateau State, Mambilla Plateau (1800m) in Taraba State, This study assessed the impact of technological change on output, of potato in Plateau State, Nigeria. It was carried out in four Local Government Areas Jos south, Bokkos, Mangu and Barkin Ladi were purposively randomly selected from eight noted for potato production. The sample size was 240 households but only 182 were used in the analysis of the data. The primary data were collected using structured questionnaire and data were collected forthnightly. Two improved potato varieties (Nicola and Lady Christy) and one local variety (Empi) were used in this study. The production systems were Furrow/Flood Irrigation and Manual watering. Cobb-Douglas production functions were estimated for the potato varieties and production systems. Chow's test's were carried out to test for structural shifts in production functions, for production system and varietal effects, homogeneity of slopes and differences in intercepts. The results showed that under Furrow/Flood Irrigation Production System, R was 0.48 for Lady Christy, 0.60 for Empi, 0.29 for Lady Christy and 0.21 for Nicola. The coefficients of the variety dummy variable were positive and statistically significant at 5% level, indicating that Nicola and Lady Christy gave higher yields than Empi (Local variety). The coefficients of the production systems dummy variables were not significant even at 10% level, so there was no difference between the yields of the improved varieties and the local variety in the two production systems. Covariance analysis for the three potato varieties grown in the two pota...